Organizing images captured by multiple image capture devices

ABSTRACT

A method for organizing images from multiple image capture devices includes allowing the determination of an offset between image capture times recorded in a first image capture device and image capture times recorded in a second image capture device, adjusting the image capture times recorded in the second image capture device by the offset to produce adjusted image capture times by a computer processor, and sequencing images taken by the first image capture device and the second image capture device in an chronological order. The sequencing is based on the image capture times for the images captured by the first image capture device and the adjusted image capture times for the images captured by the second image capture device.

The present patent application claims priority to commonly assigned U.S.provisional patent application No. 61/364,889, entitled “Organizingimages captured by multiple digital cameras” filed Jul. 16, 2010 by thesame inventors, the content of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

In recent years, photography has been transformed from chemical basedtechnologies to digital imaging technologies. A phenomenon associatedwith digital photography is the large number of images that an averageuser can generate and have to organize in a short period of time. Atypical vacation trip can easily produce hundreds to thousands ofdigital images. Digital images can be captured by different types ofimaging devices. A typical household may own a number of image capturedevices such as single-lens reflex (SLR) and point-and-shoot digitalcameras manufactured by Canon, Nikon, Kodak, HP, etc., camera phonesmade by Nokia, Apple Computer, Samsung, HTC, Motorola, etc., and videocameras that can take still images.

The captured images can be stored on local computer devices or remoteservers, and can be viewed locally or online. Digital images can also beused to create personalized image products such as photo books, photocalendars, photo cards, photo stationeries, photo prints, photo mugs,photo T-shirts, and so on. Some image products (e.g. photo books,calendars, and collages) can incorporate tens to hundreds of imagesobtained by different image capture devices. Some image usages involvedigital images taken by different users. For example, an image sharesite may publish a large number of images captured with differentdevices by different users that are associated with each other in anextended family, as classmates, members of a club or a sport team, etc.

A challenge associated with organizing digital images is that thedigital images from different imaging devices often do not carryconsistent information. The file names from different cameras aredifferent. Some image capture devices include EXIF (Exchangeable imagefile format) header files; but some don't. Additionally, the informationstored in the EXIF header files may not be correct. For example, manyusers do not set the clocks in their digital cameras. The clock times ofmany cameras are still based on the default start times (12:00:002006/1/1, 12:00:00 2008/1/1/) originally set in the factories.

There is therefore a need to effectively organize a large number ofimages to allow users to conveniently create image products and shareimages.

SUMMARY OF THE INVENTION

In one aspect, the present application relates to a computer system thatincludes one or more computer processors that can enable thedetermination of an offset between image capture times recorded in afirst image capture device and image capture times recorded in a secondimage capture device, to adjust the image capture times recorded in thesecond image capture device by the offset to produce adjusted imagecapture times, and to sequence images taken by the first image capturedevice and the second image capture device in an chronological order,wherein the sequencing is based on the image capture times for theimages captured by the first image capture device and the adjusted imagecapture times for the images captured by the second image capturedevice.

In another aspect, the present application relates to a method fororganizing images from multiple image capture devices. The methodincludes allowing the determination of an offset between image capturetimes recorded in a first image capture device and image capture timesrecorded in a second image capture device; adjusting the image capturetimes recorded in the second image capture device by the offset toproduce adjusted image capture times by a computer processor; andsequencing images taken by the first image capture device and the secondimage capture device in an chronological order, wherein the sequencingis based on the image capture times for the images captured by the firstimage capture device and the adjusted image capture times for the imagescaptured by the second image capture device.

Implementations of the system may include one or more of the following.The method can further include sequencing images captured by the firstimage capture device based on the image capture times recorded by thefirst image capture device; and sequencing images captured by the secondimage capture device based on the image capture times recorded by thesecond image capture device. The step of allowing the determination ofan offset can include sampling image counts of images captured by thefirst image capture device at a first time interval to create a firstimage count distribution (ICD); sampling image counts of images capturedby the second image capture device at the first time interval to createa second ICD; computing a first correlation function between the firstICD and the second ICD by a computer; and using the correlation functionto determine a first value for the offset between image capture times inthe first image capture device and the second image capture device. Thefirst value for the offset can be determined by the maximum value incorrelation function. The first time interval can be in a range fromabout 2 min to about 45 min. The step of allowing the determination ofan offset further can include sampling image counts of images capturedby the first image capture device at a second time interval to create athird image count distribution (ICD); sampling image counts of imagescaptured by the second image capture device at the first time intervalto create a fourth ICD; computing a second correlation function betweenthe third ICD and the fourth ICD; using the correlation function todetermine a second value for the offset between image capture times inthe first and the second image capture devices; and selecting one of thefirst value and the second value, wherein the image capture timesrecorded in the second image capture device are adjusted by the selectedone of the first value and the second value. The step of allowing thedetermination of an offset further comprises: allowing a user to select,using a computer device, a first image captured by the first imagecapture device and a second image captured by the second image capturedevice and to identify the first image and the second image to be takenat about the same time; and computing the offset based on image capturetimes of the first image and the second image. The offset is related tothe difference between the clock times in the first image capture deviceand the second image capture device. The method can further includeallowing the images taken by the first image capture device and thesecond image capture device in the chronological order to be displayedon a computer device. The computer device can be connected to thecomputer processor via a computer network. The computer processor canreside in the computer device. The first image capture device and thesecond image capture device can include at least one of a digitalcamera, a camera phone, a video camera, a laptop computer, or a tabletcomputer. The method can further include allowing images from the firstimage capture device and the second image capture device to beincorporated, in the chronological order, into the design of an imageproduct. The method can further include allowing images from the firstimage capture device and the second image capture device to be publishedin the chronological order on a web media. The web media can include ablog page.

Embodiments may include one or more of the following advantages. Thedisclosed methods and systems can significantly save users' times spenton organizing a large number of digital images captured by differentimage capture devices. The disclosed methods and systems canintelligently compensate for discrepancies in clock times betweendifferent image capture devices, and automatically sequence images fromdifferent image capture devices in a correct chronological order. Thedisclosed methods and systems can make it easier for users to use imagesto tell a story about their memories. The disclosed methods and systemsalso make it easier for users to create image products such as photobooks and create photo blog pages using images captured by differentimage capture devices.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram for an imaging service system for producingpersonalized image products.

FIG. 2 is a flowchart for intelligently organizing images from differentimage capture devices.

FIG. 3 illustrates a user interface comprising images obtained bydifferent image capture devices.

FIG. 4 illustrates image counts along the capture time respectivelyrecorded by different image capture devices.

FIG. 5 illustrates user enabled correlation between images obtained bydifferent image capture devices at the user interface shown in FIG. 3.

FIG. 6 illustrates the correlation and offsets between the capture timesnatively recorded by different image capture devices.

FIG. 7 shows steps for automatically determining offset between imagecapture times in two image capture devices.

FIG. 8 illustrates image counts sampled at predetermined time intervalsalong the image capture time for each of the image capture devices.

FIG. 9 shows a correlation function of the image count distributions fortwo cameras.

FIG. 10 shows image counts plotted against adjusted image capture times.

FIG. 11 shows the intelligently sequenced images taken by differentimage capture devices.

Although the invention has been particularly shown and described withreference to multiple embodiments, it will be understood by personsskilled in the relevant art that various changes in form and details canbe made therein without departing from the spirit and scope of theinvention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, an imaging service system 10 can enable users 70,71 to organize and share images via a wired network or a wirelessnetwork 51. Optionally, the imaging service system 10 can also fulfillimage products for the users 70, 71. The imaging service system 10includes a data center 30, one or more product fulfillment centers 40and 41, and a computer network 80 that facilitates the communicationsbetween the data center 30 and the product fulfillment centers 40 and41.

The data center 30 can include a server 32 for communicating andreceiving input from the users 70, 71, a data storage device 34 forstoring user data, image and design data, and a computer processor 36for rendering images, organizing images, and processing orders. The userdata can include account information, discount information, and orderinformation associated with the user. A website can be powered by theservers 32 and can be accessed by the user 70 using a computer device 60via the Internet 50, or by the user 71 using a wireless device 61 viathe wireless network 51.

The imaging service system 10 can provide products that require userparticipation in designs and personalization. Examples of these productsinclude the personalized image products provided by Shutterfly, Inc. Inthe present disclosure, the term “personalized” refers to theinformation that is specific to the recipient, the user, the giftproduct, and the occasion, which can include personalized content,personalized text messages, personalized images, and personalizeddesigns that can be incorporated in the image products. The content ofpersonalization can be provided by a user or selected by the user from alibrary of content provided by the service provider. The term“personalized information” can also be referred to as “individualizedinformation” or “customized information”.

Personalized image products can include users' photos, personalizedtext, personalized designs, and content licensed from a third party.Examples of personalized image products may include photo books,personalized greeting cards, photo stationery, photo or image prints,photo posters, photo banners, photo playing cards, photo T-shirts, photocoffee mugs, photo pads, photo key-chains, photo collectors, photocoasters, or other types of photo gift or novelty item. Photo bookgenerally refers to a bound multi-page product that includes at leastone image on a book page. Photo books can include photo albums,scrapbooks, bound photo calendars, or photo snap books, etc.

The user 70 or her family may own multiple cameras 62, 63. The user 70transfers images from cameras 62, 63 to the computer device 60. The user70 can edit, organize images from the cameras 62, 63 on the computerdevice 60. The computer device 60 can be in many different forms: apersonal computer, a laptop, or tablet computer (e.g. IPad), a mobilephone etc. The camera 62 can include a camera that is integrated orconnected with in the computer device 60. For example, laptop computersor computer monitors can include built-in camera for picture taking. Theuser 70 can also print pictures using a printer 65 and make imageproducts based on the images from the cameras 62, 63. The cameras 62, 63can include a digital camera, a camera phone, a video camera capable oftaking still images, a laptop computer, or a tablet computer.

The images from the cameras 62, 63 can also be uploaded to the server 32to allow the user 70 to organize and render images at the website, sharethe images with others, and design or order image product using theimages from the cameras 62, 63. The wireless device 61 can include amobile phone, a tablet computer, or a laptop computer, etc. The wirelessdevice 61 can include a built-in camera (e.g. in the case of a cameraphone). The images taken by the user 71 using the wireless device 61 canalso be uploaded to the data center 30. If users 70, 71 are members of afamily or associated in a group (e.g. a soccer team), the images fromthe cameras 62, 63 and the mobile device 61 can be grouped together tobe incorporated into an image product such as a photo book, or used in ablog page for an event such as a soccer game.

In accordance to the present invention, the images from different imagecapture devices can be intelligently organized on a standalone computerdevice such as the computer device 60 and the wireless device 61, or,over the computer network, by a remote computer system such as the datacenter 30 and the computer processor 36. Referring to FIGS. 2 and 3, thedigital images from different image capture devices are first separatedby file names and/or their respective manufacturers and models (step210, FIG. 2). Digital images from different image capture devices (suchas cameras 62, 63, video cameras, or a mobile phone) usually havedifferent file names such as DSC0205-DSC0208, PICT8500-PICT8503,IMG2808-2811 . . . etc., as shown in a user interface 300. The numbersafter the alphabet characters indicate the sequence in which the imagesare captured by the specific image capture device. For example, theimages from three cameras are separated into different groups 10, 20,and 30.

The user interface 300 can be provided by a software applicationinstalled on the computer device 60 (or the mobile device 61), whichfacilitates image viewing, organization, editing, rendering, and/orimage product design using images on the same computer device (or mobiledevice). The user interface 300 can also be implemented as a web browseror a client application, which serves as a communication interface witha remote server such as server 32 via a computer network such as theInternet 50 or the wireless network 51.

The capture times of the images are then extracted from the images fromeach image capture device (step 220, FIG. 2). The image capture timesare often stored in the EXIF files associated with the images. Theimages from each image capture device are then sequenced using thenative image capture times originally stored by the image capturedevices (step 230, FIG. 2). Although the clock of an image capturedevice may not reflect the real time and date, the native capture timesof the image capture device can provide correct relative chronologicalorder (but may not reflect the correct absolute times) for imagescaptured by that image capture device. For example, the imagesDSC0205-DSC0208 in the group 10 are chronologically sequenced accordingto their respective natively recorded capture times. Similarly, theimages in the group 20 and the group 30 are respectively sequenced usingthe image capture times of their respective image capture devices.

However, because the clocks of different image capture devices are oftennot correctly set, the images in the different groups 10, 20, 30 cannotbe sequenced using a common capture time. For images taken at the sametime, the image capture times recorded by different image capturedevices often differ by an offset because some or all of the imagecapture devices do not have the correct dates and times.

The offsets on image capture times between different image capturedevices can be determined manually or automatically (step 240, FIG. 2).FIG. 4 illustrates image capture times of images captured by differentcameras. Image captures by camera 1, camera 2, and camera 3 are plottedagainst their respective native capture times. Images captured by thethree cameras are clustered around events such as “zoo”, “beach”, and“dinner”, which however are recorded with different the image capturetimes on different cameras.

In some embodiments, the offset time can be manually determined with theassistance of a user. As shown in FIG. 5, the user can use the imagecontent as clues to select images in different groups 10, 20, 30 thatwere captured at approximately the same times. For example, if imagesDSC0205, PICT8502, IMG2809 include the same scene (e.g. kids buildingsand castle on a beach), the user can remember or infer that theseimages from different cameras are taken at about the same time. The usercan click and highlight one image (e.g. DSC0205, PICT8502, IMG2809) ineach group 10, 20, 30 to identify these images as being taken at aboutthe same time.

Referring to FIG. 6, the correlations between images DSC0205, PICT8502,IMG2809 are illustrated by the double-headed arrows connecting theimages from different cameras. The offset between cameras 1 and camera 2is indicated by offset 21. The offset 21 is related to the differencesbetween the clock times of camera 1 and camera 2. The offset betweencameras 1 and camera 3 is indicated by offset 31. Once the images takenby different cameras at about the same time are correlated by the user,the computer device 60 or the computer processor 36 (FIG. 1) cancalculate offset 21 (step 240, FIG. 2) by subtracting the capture timeof the image PICT8502 by the image capture time of the image DSC0205.Similarly, the computer device 60 or the computer processor 36 (FIG. 1)can calculate offset 31 (step 240, FIG. 2) by subtracting the capturetime of the image IMG2809 by the image capture time of the imageDSC0205.

In some embodiments, referring to FIG. 7, the offsets between imagecapture times of different cameras can be automatically determined by acomputer processor in the computer device 60 or the mobile device 61, orthe computer processor 36. A time interval e.g. 5 min or 10 min isselected (step 710). For each camera, the image counts can be sampled ata along its natively recorded image capture time, in other words, allimages captured in each time interval is summed up and recorded as theimage count for that time interval (steps 720, 730). The resulting imagecounts distributions (ICDs) for images from different camera 1 (ICD1),camera 2 (ICD2), and camera 3 (ICD3) are shown in FIG. 8. The imagestaken by the three cameras at the same event ICDs also differ by offsetssimilar to the raw image counts as shown in FIGS. 4 and 6.

Referring to FIG. 9, a correlation function 12 between ICD1 and ICD2 canbe calculated (step 740) by the computer device 60, the mobile device61, or the computer processor 36 (FIG. 2). Most pictures on camera 1 andcamera 2 are both taken mostly at “photographic events” (e.g. zoo,beach). Picture taking at other times are few and not correlated betweenthe two cameras. The correlation between ICD2 and ICD1 should be peakedat the offset 21, when plotted as a function of the delta capture time21 (the difference between the capture times of the two cameras). Inother words, the maximum value of the correlation function can be usedto determine the offset 21 in the capture times (or the clock and dates)between the two cameras (step 750). Similarly, offset 31 can beautomatically determined by the computer device 60 or the computerprocessor 36 (FIG. 2) by computing the correlation function between ICD3and ICD1.

The precision and the accuracy of the offset times can be improved byvarying the time interval for sampling the image counts. While shorttime intervals (e.g. 15 seconds, 30 seconds, 1 min, etc.) can be precisein sampling image capture times, the image count within each timeinterval is low and so is the chance that two cameras capture images atexactly the same moment. The correlation functions can often be noisyfor accurately determining offset. On the other hand, although long timeintervals (e.g. 60 min, 90 min, etc.) tend to include higher imagecounts per time interval, there is a higher probability that differentevents are covered in the same time interval, which decreases thespecificity in correlating different events. By selecting a second timeinterval (step 760), a second offset value can be determined using steps720-750 between the image capture times of the first and second cameras(step 770). The offset value can be selected among different valuesusing the high signal-to-noise ratio (e.g. the maximum value relative tobackground) at the small peak width in the correlation function (step780). Varying the duration of time interval can optimize the temporalprecision (relating to peak width) and the accuracy (relating tosign-to-noise ratio) in the determination of the offset. For example, anoptimal period may be found in a range including 2 min, 5 min, 10 min,15, min, 20 min, 30 min, and 45 min time intervals for sampling imagecounts in ICDs.

Once the offsets (e.g. Offset 12 and Offset 13) in the capture timesbetween cameras are determined (automatically or manually), the offsetsare subtracted from the respective capture times of the different imagecapture devices (step 250, FIG. 2) to product adjusted capture times.For example, the capture time of camera 1 can be used as a commonreference. The capture times of images by camera 2 are subtracted byoffset 21 such that the image capture times of images obtained by bothcamera 1 and camera 2 are based on the original capture time of camera1. Similarly, the capture times of images by camera 3 are subtracted byoffset 31. The adjusted capture times are stored in association withtheir respective images obtained by cameras 2 and 3 (step 260, FIG. 2).The adjusted capture times can for example be stored in the respectiveEXIF files or in a separate metadata field. Since the native capturetime of camera 1 is used as the standard base capture time, noadjustment is needed for the capture times for images from camera 1.FIG. 10 shows that the image counts of camera 2 and camera 3 are plottedagainst the adjusted image capture times.

The images from image capture devices (camera 2-3) are sequenced usingtheir respective adjusted capture times (step 270, FIG. 2). The imagesobtained by camera 1 are based on their originally recorded imagecapture times because they are used as the reference for determining theoffset (so the adjusted image capture times for camera 1 are the same asthe original image capture times). The images from different imagecapture devices (cameras 1-3) are combined in a list in the userinterface 300, and sequenced in a chronological order based on adjustedimage capture times (cameras 2, 3) on the computer device 60, the mobiledevice 61, or enabled by the server 32, as shown in FIG. 11 (step 280,FIG. 2).

In the present invention, it is not necessary that the capture time usedas the common reference is set as the correct time and date. In somecases, none of the cameras has the time and date. The images fromdifferent cameras or other image capture devices can be chronicallysequenced without knowing or using the correct date or time.

After the images from different cameras are combined in a single groupin the user interface 300 and sequenced in a chronological order basedon adjusted image capture times, the user 70, 71 can create an imageproduct such as a photobook or a web media such as a blog page, usingthe images from different image capture devices based on the adjustedimage capture times (step 290, FIG. 2). The web media containing theimages can be published by the server 32 via computer network in thechronicle sequence based on the adjusted image capture time.

The image product such as the photobook can be locally produced, orordered by the user 70, 71 at the data center 30 and then sent toproduct a fulfillment center 40, 41, which produces the orderedproducts, and deliver the recipients (100, 105 in FIG. 1) specified bythe user 70, 71. The product fulfillment center 40 includes a server 42,and the storage and retrieving systems for pre-made off-the-shelfproducts. For the fulfillments of personalized image products, theproduct fulfillment center 40 can include one or more printers 45 forprinting images, finishing equipment 46 for operations such as cutting,folding, binding the printed image sheets, and shipping stations 48 forverifying the orders and shipping the orders to recipients 100 and 105.Examples of the printers 45 include can be digital photographicprinters, offset digital printers, digital printing presses, and inkjetprinters. The finishing equipment 46 can perform operations forfinishing a complete image product other than printing, for example,cutting, folding, adding a cover to photo book, punching, stapling,gluing, binding, and envelope printing and sealing. The shippingstations 48 may perform tasks such as packaging, labeling, packageweighing, and postage metering.

An advantageous application for chronically sequencing images fromdifferent capture devices is the creation of photobooks. A photobook mayutilize hundreds of images from different cameras. Most users like toplace images on the book pages in a chronological order: earlier imagesappear on the first few pages while later images appear on the laterpages. Once the images are correctly sequenced, it is much easier for auser to select and place images onto the pages. In some embodiments,chronically sequenced images allow the images to be automatically placedon the book pages, which can greatly reduce the time and effort requiredfor a user to create a photobook.

Detailed configurations and steps can differ from the examples describedabove without deviating from the spirit of the present invention. Thedisclosed methods are not limited to applications over computer network;rather, they are applicable to standalone computer devices such aspersonal computers, laptop computers, tablet computers, mobile devices,and other computing devices that can help users to organize images. Theimage capture devices, the computer devices, and the wireless devicesare not limited to the examples used above.

What is claimed is:
 1. A method for organizing images from multipleimage capture devices, comprising: sequencing images captured by a firstimage capture device based on the image capture times recorded by thefirst image capture device; sequencing images captured by a second imagecapture device based on the image capture times recorded by the secondimage capture device; determining an offset between image capture timesrecorded in the first image capture device and image capture timesrecorded in the second image capture device, wherein the step ofdetermining an offset comprises: sampling image counts of imagescaptured by the first image capture device at a first time interval tocreate a first image count distribution (ICD); sampling image counts ofimages captured by the second image capture device at the first timeinterval to create a second ICD; computing a first correlation functionbetween the first ICD and the second ICD by a computer; and using thefirst correlation function to determine a first value for the offsetbetween image capture times in the first image capture device and thesecond image capture device; and adjusting the image capture timesrecorded in the second image capture device by the first value for theoffset to produce adjusted image capture times by a computer processor.2. The method of claim 1, further comprising: after the step ofadjusting, sequencing the images taken by the second image capturedevice based on the adjusted image capture times.
 3. The method of claim1, wherein the first value for the offset is determined by a maximumvalue in the first correlation function.
 4. The method of claim 1,wherein the first time interval is in a range from about 2 minutes toabout 45 minutes.
 5. The method of claim 1, wherein the step ofdetermining an offset further comprises: sampling image counts of imagescaptured by the first image capture device at a second time interval tocreate a third image count distribution (ICD); sampling image counts ofimages captured by the second image capture device at the second timeinterval to create a fourth ICD; computing a second correlation functionbetween the third ICD and the fourth ICD; using the second correlationfunction to determine a second value for the offset between imagecapture times in the first and the second image capture devices; andselecting one of the first value and the second value, wherein the imagecapture times recorded in the second image capture device are adjustedby the selected one of the first value and the second value.
 6. Themethod of claim 1, wherein the step of determining an offset furthercomprises: allowing a user to select, using a computer device, a firstimage captured by the first image capture device and a second imagecaptured by the second image capture device and to identify the firstimage and the second image as having been taken at about the same time;and computing the offset based on image capture times of the first imageand the second image.
 7. The method of claim 1, wherein the first valuefor the offset is related to a difference between clock times in thefirst image capture device and the second image capture device.
 8. Themethod of claim 1, further comprising: allowing a computer device todisplay the images taken by the first image capture device and thesecond image capture device in a chronological order.
 9. The method ofclaim 8, wherein the computer device is connected to the computerprocessor via a computer network.
 10. The method of claim 8, wherein thecomputer processor resides in the computer device.
 11. The method ofclaim 1, wherein the first image capture device and the second imagecapture device comprise at least one of a digital camera, a cameraphone, a video camera, a laptop computer, or a tablet computer.
 12. Themethod of claim 1, further comprising: allowing the design of an imageproduct to incorporate the images from the first image capture deviceand the second image capture device in a chronological order.
 13. Themethod of claim 1, further comprising: allowing a web media to publishthe images from the first image capture device and the second imagecapture device in a chronological order.
 14. The method of claim 13,wherein the web media comprises a blog page.
 15. A computer system,comprising: one or more computer processors configured to determine anoffset between image capture times recorded in a first image capturedevice and image capture times recorded in a second image capturedevice, to sample image counts of images captured by the first imagecapture device at a first time interval to create a first image countdistribution (ICD), to sample image counts of images captured by thesecond image capture device at the first time interval to create asecond ICD, to compute a first correlation function between the firstICD and the second ICD, to use the first correlation function todetermine a first value for the offset between image capture times inthe first image capture device and the second image capture device, toadjust the image capture times recorded in the second image capturedevice by the first value for the offset to produce adjusted imagecapture times, and to sequence images taken by the second image capturedevice based on the adjusted image capture times.
 16. The computersystem of claim 15, wherein the first value for the offset is determinedby a maximum value in the first correlation function.
 17. The computersystem of claim 15, wherein the first time interval is in a range fromabout 2 minutes to about 45 minutes.
 18. The computer system of claim15, wherein the one or more processors are configured to allow a user toidentify a first image captured by the first image capture device and asecond image captured by the second image capture device which are takenat about the same time, wherein the one or more processors areconfigured to compute the offset based on image capture times of thefirst image and the second image.